Systems and methods for bundling resource blocks in a wireless communication network

ABSTRACT

A base station for use in a wireless network is operable to communicate with a plurality of mobile stations. The base station transmits a downlink frame to a first mobile station. The downlink frame comprises time-frequency resource elements allocated in a plurality of physical resource blocks. The base station transmits the plurality of physical resource blocks in bundles having a bundle size that is a function of the system bandwidth configuration and the base station uses the same precoder for all physical resource blocks in the same bundle. The bundle size is from one physical resource block to three physical resource blocks.

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

This application a continuation of U.S. Non-Provisional patentapplication Ser. No. 13/083,193 filed Apr. 8, 2011 and entitled “SYSTEMSAND METHODS FOR BUNDLING RESOURCE BLOCKS IN A WIRELESS COMMUNICATIONSYSTEM,” and claims priority to U.S. Provisional Patent Application No.61/324,242, filed Apr. 14, 2010, entitled “RESOURCE BLOCK BUNDLING SIZEFOR LTE-A SYSTEMS.” The content of the above-identified patent documentsis hereby incorporated by reference.

TECHNICAL FIELD

The present application relates generally to wireless communicationsand, more specifically, to a method and system for enabling resourceblock bundling.

BACKGROUND

In 3^(rd) Generation Partnership Project Long Term Evolution (3GPP LTE),Orthogonal Frequency Division Multiplexing (OFDM) is adopted as adownlink (DL) transmission scheme.

GPP LTE (Long Term Evolution) standard is the last stage in therealization of true 4th generation (4G) mobile telephone networks. Mostmajor mobile carriers in the United States and several worldwidecarriers have announced plans to convert their networks to LTE beginningin 2009. LTE is a set of enhancements to the Universal MobileTelecommunications System (UMTS). Much of 3GPP Release 8 focuses onadopting 4G mobile communications technology, including an all-IP flatnetworking architecture.

The 3GPP LTE standard uses orthogonal frequency division multiplexing(OFDM) for the downlink (i.e., from the base station to the mobilestation). Orthogonal frequency division multiplexing (OFDM) is amulti-carrier transmission technique that transmits on many orthogonalfrequencies (or subcarriers). The orthogonal subcarriers areindividually modulated and separated in frequency such that they do notinterfere with one another. This provides high spectral efficiency andresistance to multipath effects.

In Release 8 LTE systems, a user equipment (UE) or mobile station (MS)is required to perform channel estimation based on common referencesignals (CRSs) over the entire bandwidth. Once channel estimation isperformed, the mobile station (or UE) performs demodulation based ondifferent transmission modes indicated by the different formats of thedownlink control information. For example, when downlink spatialmultiplexing is performed, downlink control information (DCI) format 2is used and the mobile station performs demodulation based on theresource assignment and TPMI (transmission PMI) contained in the DCIformat.

In 3GPP Technical Specification No. 36.212, version 8.8.0, “E-UTRA,Multiplexing and Channel Coding” (December 2009), the definition of TPMIis defined in Table 5.3.3.1.5-4 (2 antenna ports) and in Table5.3.3.1.5-5 (4 antenna ports) of Section 5.3.3.1.5. The 3GPP TechnicalSpecification No. 36.212, version 8.8.0, is hereby incorporated byreference into the present disclosure as if fully set forth herein.

The base station (or eNodeB) indicates to the mobile station (MS) oruser equipment (UE) whether the base station (BS) is implementingwideband precoding or subband precoding based on mobile station feedbackand the mobile station performs downlink demodulation accordingly.

In LTE-Advanced (LTE-A) systems, the downlink demodulation is based ondedicated reference signals (DRS), which are UE-specific referencesignals (UE-RS).

In LTE-Advanced systems, demodulation of the data channel is based onthe precoded UE-specific reference signal. That is, the referencesignals are precoded using the same precoder as the data channel asdescribed in 3GPP Document No. R1-090529, “Way Forward On CoMP And MIMODL RS,” Outcome of Ad Hoc Discussions (January 2009), and 3GPP DocumentNo. R1-091066, “Way Forward On Downlink Reference Signals For LTE-A,”(March 2009), both of which are hereby incorporated by reference intothe present disclosure as if fully set forth herein.

Reference signals (RSs) targeting PDSCH demodulation (for LTE-Aoperation) are also UE-specific and are transmitted only in scheduledresource blocks (RBs) and the corresponding layers. Different layers cantarget the same or different UEs. The design principle is an extensionof the concept of Rel-8 UE-specific RS (used for beamforming) tomultiple layers. Reference signals on different layers are mutuallyorthogonal. Reference signals and data are subject to the same precodingoperation, and complementary use of Rel-8 CRS by the UE is notprecluded.

In Document No. R1-094413, “Way Forward On The Details Of DCI Format 2BFor Enhanced DL Transmission,” 3GPP RAN1#58bis, Miyazaki (October 2009),which is hereby incorporated by reference into the present disclosure asif fully set forth herein, an agreement has been made for DCI format 2B.In the agreement, the DCI Format 2B is based on DCI Format 2A. One (1)bit is added for the source channel identifier (SC-ID) and the Swap Flagis removed. For rank 1 transmission, the new data indicator (NDI) bit ofthe disabled transport block is re-used to indicate port information. Avalue of 0 is used to indicate an enabled transport block (TB)associated with port 7. A value of 1 is used to indicate an enabledtransport block associated with port 8. For rank 2 transmission, TB1 isassociated with port 7, and TB2 associated with port 8. DCI format 2 Ccan be constructed based on DCI format 2B for Release 10 transmissionmodes for facilitating dynamic SU- and MU-MIMO switching.

Since an eNodeB could potentially perform resource block (RB)-basedprecoding, the baseline granularity for channel estimation anddemodulation is one resource block (RB). However, as disclosed in 3GPPDocument No. R1-093105, “UE-RS Patterns for LTE-A”, Qualcomm Europe(August 2009), which is hereby incorporated by reference into thepresent disclosure as if fully set forth herein, “resource block (RB)bundling” (i.e., bundling contiguous RBs together to perform channelestimation and demodulation) will help higher rank (i.e., rank 5 to 8)transmissions achieve adequate channel estimation accuracy along withlow overhead. It is also noted that RB bundling could be used to balancethe transmission power imbalance across OFDM symbols for some high rankDM-RS patterns, as disclosed in 3GPP Document No. R1-094575, “DiscussionOn DM-RS For LTE-Advanced”, Samsung (November 2009); 3GPP Document No.R1-094438, “On Rel-10 DM RS Design For Rank 5-8”, Ericsson, ST-Ericsson(November 2009), and 3GPP Document No. R1-094548, “Further InvestigationOn DMRS Design For LTE-A”, CATT (November 2009), which are herebyincorporated by reference into the present disclosure as if fully setforth herein.

FIGS. 3A-3C illustrate dedicated reference signal (DRS) patterns thatsupport two and four layer transmissions according to an embodiment ofthis disclosure. Dedicated reference signal (DRS) patterns 301 and 303illustrate pilot patterns that can support up to two (2) layertransmissions. DRS resource elements labeled with (0,1) in DRS pattern301 carry dedicated reference signals for layer 0 and 1 with thereference signals of the two layers code-division multiplexed (CDMed).Similarly, for DRS resource elements labeled with (2,3) in DRS pattern303 carry dedicated reference signals for layer 2 and 3 with thereference signals of the two layers code-division multiplexed (CDMed).

In the two adjacent DRS resource elements labeled with (0,1), DRSsymbols [r0 r1] for layer 0 are mapped to the two resource elementsspread by a Walsh code [1 1], which results in [r0 r1], while DRSsymbols r2 and r3 for layer 1 are mapped to the two resource elementsspread by a Walsh code [1 −1], which results in [r2 −r3].

DRS pattern 305 illustrates a pilot pattern that can support up to fourlayer transmissions, where the DRS resource elements are againpartitioned into two groups, those labeled with (0,1) and those with(2,3). In this pattern, the DRS resource elements labeled with (0,1)carry dedicated reference signals for layer 0 and 1 with the referencesignals of the two layers code-division multiplexed (CDMed). The DRSresource elements labeled with (2,3) carry dedicated reference signalsfor layer 2 and 3 with the reference signals of the two layerscode-division multiplexed (CDMed).

FIG. 4 illustrates DRS patterns 401 and 403, which support eight layertransmissions according to an embodiment of the disclosure. In FIG. 4,resource elements labeled with alphabet character X, where X is one ofG, H, I, J, L, K, are used for carrying a number of dedicated referencesignals among the 8 dedicated reference signals, where the number ofdedicated reference signals are CDMed. DRS pattern 401 is based onspreading factor 2 CDM across two time-adjacent resource elements withthe same alphabet character label. DRS pattern 403 is based on spreadingfactor 4 CDM across two groups of two time-adjacent resource elementswith the same alphabet character label. In this embodiment, the 8antenna ports in a Rank-8 pattern are referred to as antenna ports 4, 5,6, 7, 8, 9, 10 and 11 in the sequel to distinguish them from the antennaports in Rank-2 and Rank-4 patterns.

It is noted that in Rel-8 LTE, antenna ports 0, 1, 2, 3, 4 and 5 areused for CRS, MBSFN RS and Rel-8 DRS. Hence, if the numbering conventionextending Rel-8 LTE is followed, the new antenna port numbers will startfrom 6. Rank-2 pattern will have antenna ports (6, 7). Rank-4 patternwill have antenna ports (7, 8, 9, 10). Rank-8 pattern will have antennaports (11, 12, 13, 14, 15, 16, 17, 18).

In one embodiment of DRS pattern 401, G carries DRS (4, 5), H carriesDRS (6,7), I carries DRS (8,9) and J carries DRS (10,11). In oneembodiment of DRS pattern 403, K carries DRS (4, 5, 6, 7) and L carriesDRS (8, 9, 10, 11).

Each of the demodulation reference signal (DM-RS) patterns in FIGS.3A-3C and FIG. 4 is resource block (RB) based. Accordingly, a UE (or MS)may perform channel estimation and demodulation per resource block.Alternatively, if resource block bundling is supported, the UE (or MS)may perform channel estimation and demodulation jointly across bundledresource blocks. In this way, the performance of channel estimation anddemodulation can be improved.

Resource block-bundling gain is achieved only when a base station (BS oreNodeB) performs the same downlink precoding vectors across the bundledresource blocks. Accordingly, a UE or MS may perform channel estimationand demodulation over the bundled resource blocks jointly.

In other words, resource block bundling reduces the precodingflexibility, since the precoding vectors within the bundled resourceblocks have to be the same. This results in a trade-off between gainsfrom increasing channel interpolation span in frequency versus lossesfrom increasing frequency selective precoding granularity.

Therefore, there is a need for improved techniques for bundling resourceblocks in a wireless communication system.

SUMMARY

To overcome the above-describe deficiencies in the prior art, a basestation is provided for use in a wireless network operable tocommunicate with a plurality of mobile stations. The base station isoperable to transmit a downlink frame to a first mobile station. Thedownlink frame comprises time-frequency resource elements allocated in aplurality of physical resource blocks. The base station transmits theplurality of physical resource blocks in bundles having a bundle sizethat is a function of the system bandwidth configuration. The basestation uses the same precoder for all physical resource blocks in thesame bundle.

In one embodiment, the bundle size is from one physical resource blockto three physical resource blocks.

In another embodiment, the bundle size is equal to one physical resourceblock when the system bandwidth is less than a first threshold.

In another embodiment, the bundle size is equal to two physical resourceblocks when the system bandwidth is greater than or equal to the firstthreshold, but less than a second threshold.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like. Definitions for certainwords and phrases are provided throughout this patent document, those ofordinary skill in the art should understand that in many, if not mostinstances, such definitions apply to prior, as well as future uses ofsuch defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an exemplary wireless network that transmits messagesin the uplink according to the principles of the disclosure;

FIG. 2A is a high-level diagram of an orthogonal frequency divisionmultiple access (OFDMA) transmitter according to one embodiment of thedisclosure;

FIG. 2B is a high-level diagram of an OFDMA receiver according to oneembodiment of the disclosure;

FIGS. 3A-3C illustrate dedicated reference signal (DRS) patterns thatsupport two and four layer transmissions according to an embodiment ofthe disclosure;

FIG. 4 illustrates DRS patterns that support eight layer transmissionsaccording to an embodiment of the disclosure;

FIG. 5 illustrates a bundling size of M=2 according to an embodiment ofthe disclosure;

FIG. 6 illustrates bundling of physical resource blocks for a particularresource allocation and virtual resource blocks of localized typeaccording to an embodiment of the disclosure;

FIG. 7 illustrates bundling of physical resource blocks for a particularresource allocation and virtual resource blocks of localized typeaccording to another embodiment of the disclosure; and

FIGS. 8A, 8B and 8C illustrate TABLES 1-3, which provide examples ofbundling sizes determined by downlink system bandwidth configuration.

DETAILED DESCRIPTION

FIGS. 1 through 8, discussed below, and the various embodiments used todescribe the principles of the disclosure in this patent document are byway of illustration only and should not be construed in any way to limitthe scope of the disclosure. Those skilled in the art will understandthat the principles of the present disclosure may be implemented in anysuitably arranged wireless communication system.

FIG. 1 illustrates exemplary wireless network 100, which transmitsmessages according to the principles of the present disclosure. In theillustrated embodiment, wireless network 100 includes base station (BS)101, base station (BS) 102, base station (BS) 103, and other similarbase stations (not shown). Base station 101 is in communication withInternet 130 or a similar IP-based network (not shown).

Depending on the network type, other well-known terms may be usedinstead of “base station,” such as “eNodeB” or “access point”. For thesake of convenience, the term “base station” shall be used herein torefer to the network infrastructure components that provide wirelessaccess to remote terminals.

Base station 102 provides wireless broadband access to Internet 130 to afirst plurality of mobile stations within coverage area 120 of basestation 102. The first plurality of subscriber stations includes mobilestation 111, which may be located in a small business (SB), mobilestation 112, which may be located in an enterprise (E), mobile station113, which may be located in a WiFi hotspot (HS), mobile station 114,which may be located in a first residence (R), mobile station 115, whichmay be located in a second residence (R), and mobile station 116, whichmay be a mobile device (M), such as a cell phone, a wireless laptop, awireless PDA, or the like.

For sake of convenience, the term “mobile station” is used herein todesignate any remote wireless equipment that wirelessly accesses a basestation, whether or not the mobile station is a truly mobile device(e.g., cell phone) or is normally considered a stationary device (e.g.,desktop personal computer, vending machine, etc.). In other systems,other well-known terms may be used instead of “mobile station”, such as“subscriber station (SS)”, “remote terminal (RT)”, “wireless terminal(WT)”, “user equipment (UE)”, and the like.

Base station 103 provides wireless broadband access to Internet 130 to asecond plurality of mobile stations within coverage area 125 of basestation 103. The second plurality of mobile stations includes mobilestation 115 and mobile station 116. In an exemplary embodiment, basestations 101-103 may communicate with each other and with mobilestations 111-116 using OFDM or OFDMA techniques.

While only six mobile stations are depicted in FIG. 1, it is understoodthat wireless network 100 may provide wireless broadband access toadditional mobile stations. It is noted that mobile station 115 andmobile station 116 are located on the edges of both coverage area 120and coverage area 125. Mobile station 115 and mobile station 116 eachcommunicate with both base station 102 and base station 103 and may besaid to be operating in handoff mode, as known to those of skill in theart.

FIG. 2A is a high-level diagram of an orthogonal frequency divisionmultiple access (OFDMA) transmit path 200. FIG. 2B is a high-leveldiagram of an orthogonal frequency division multiple access (OFDMA)receive path 250. In FIGS. 2A and 2B, the OFDMA transmit path 200 isimplemented in base station (BS) 102 and the OFDMA receive path 250 isimplemented in mobile station (MS) 116 for the purposes of illustrationand explanation only. However, it will be understood by those skilled inthe art that the OFDMA receive path 250 may also be implemented in BS102 and the OFDMA transmit path 200 may be implemented in MS 116.

The transmit path 200 in BS 102 comprises a channel coding andmodulation block 205, a serial-to-parallel (S-to-P) block 210, a Size NInverse Fast Fourier Transform (IFFT) block 215, a parallel-to-serial(P-to-S) block 220, an add cyclic prefix block 225, and an up-converter(UC) 230.

The receive path 250 in MS 116 comprises a down-converter (DC) 255, aremove cyclic prefix block 260, a serial-to-parallel (S-to-P) block 265,a Size N Fast Fourier Transform (FFT) block 270, a parallel-to-serial(P-to-S) block 275, and a channel decoding and demodulation block 280.

At least some of the components in FIGS. 2A and 2B may be implemented insoftware while other components may be implemented by configurablehardware or a mixture of software and configurable hardware. Inparticular, it is noted that the FFT blocks and the IFFT blocksdescribed in the present disclosure document may be implemented asconfigurable software algorithms, where the value of Size N may bemodified according to the implementation.

Channel coding and modulation block 205 receives a set of informationbits, applies coding (e.g., Turbo coding) and modulates (e.g., QPSK,QAM) the input bits to produce a sequence of frequency-domain modulationsymbols. Serial-to-parallel block 210 converts (i.e., de-multiplexes)the serial modulated symbols to parallel data to produce N parallelsymbol streams where N is the IFFT/FFT size used in BS 102 and MS 116.Size N IFFT block 215 then performs an IFFT operation on the N parallelsymbol streams to produce time-domain output signals. Parallel-to-serialblock 220 converts (i.e., multiplexes) the parallel time-domain outputsymbols from Size N IFFT block 215 to produce a serial time-domainsignal. Add cyclic prefix block 225 then inserts a cyclic prefix to thetime-domain signal. Finally, up-converter 230 modulates (i.e.,up-converts) the output of add cyclic prefix block 225 to RF frequencyfor transmission via a wireless channel. The signal may also be filteredat baseband before conversion to RF frequency.

The transmitted RF signal arrives at MS 116 after passing through thewireless channel and reverse operations performed at BS 102.Down-converter 255 down-converts the received signal to basebandfrequency and remove cyclic prefix block 260 removes the cyclic prefixto produce the serial time-domain baseband signal. Serial-to-parallelblock 265 converts the time-domain baseband signal to parallel timedomain signals. Size N FFT block 270 then performs an FFT algorithm toproduce N parallel frequency-domain signals. Parallel-to-serial block275 converts the parallel frequency-domain signals to a sequence ofmodulated data symbols. Channel decoding and demodulation block 280demodulates and then decodes the modulated symbols to recover theoriginal input data stream.

Each of base stations 101-103 may implement a transmit path that isanalogous to transmitting in the downlink to mobile stations 111-116 andmay implement a receive path that is analogous to receiving in theuplink from mobile stations 111-116. Similarly, each one of mobilestations 111-116 may implement a transmit path corresponding to thearchitecture for transmitting in the uplink to base stations 101-103 andmay implement a receive path corresponding to the architecture forreceiving in the downlink from base stations 101-103.

U.S. patent application Ser. No. 12/970,717, filed Dec. 16, 2010 andentitled “METHOD AND SYSTEM FOR ENABLING RESOURCE BLOCK BUNDLING INLTE-A SYSTEMS”, disclosed unique and novel techniques for enabling anddisabling resource block bundling. U.S. patent application Ser. No.12/970,717 was incorporated by reference above.

In an advantageous embodiment of the present disclosure, physicalresource block (PRB) bundling is enabled when the system is configuredin FDD operation mode and disabled when the system is configured in TDDoperation mode. Enabling PRB bundling means that the mobile station (orUE) may assume that a set of consecutive physical resource blocks usethe same precoder for the corresponding physical downlink shared channel(PDSCH) from the serving base station (BS) to the mobile station.Disabling PRB bundling means that the mobile station (or UE) may onlyassume that the precoder stays the same within one physical resourceblock (PRB).

The awareness of the mobile station (MS) of FDD operation mode and TDDoperation mode may be realized through downlink frame structure. Thatis, when the mobile station is configured in frame structure type 1,then the mobile station operates in FDD mode and PRB bundling is enabled(or turned on). Alternatively, when the mobile station is configured inframe structure type 2, the mobile station operates in the TDD mode andPRB bundling is disabled (or turned off).

In an advantageous embodiment of the present disclosure, the totalsystem bandwidth is partitioned into disjoint precoding subsets, wherethe precoding subset consists of M consecutive physical resource blocks(PRBs). In this case, a precoding subset i is composed of PRBs with PRBnumbers:

n_(PRB) = M × i, …  , min (M × (i + 1) − 1, N_(RB)^(DL)), where${i = 0},\ldots \mspace{14mu},{\left\lfloor \frac{N_{RB}^{DL}}{M} \right\rfloor.}$

The value N_(RB) ^(DL) is the total number of resource blocks within adownlink system bandwidth (also known as a downlink system bandwidthconfiguration in LTE). When a mobile station is scheduled in N PRBs, themobile station may assume the same precoder is applied to all PRBswithin a precoding subset.

In one embodiment of the present disclosure, the size of the precodingsubset (bundling size) is the same for all downlink system bandwidthconfigurations defined in LTE.

A wireless network according to the principles of the present disclosureimplements a bundling size that accounts for the tradeoff between thequality of channel estimation and the flexibility of precoders used in aphysical resource block. As is known, a base station must use the sameprecoder for all allocated PRBs in the same bundle. If the bundling sizeis too big, flexibility in precoding is reduced since all PRBs in thesame bundle use the same precoders. However, if bundling size is toosmall, then channel estimation suffers. A mobile station (or UE) obtainsbetter channel estimation for a particular precoder if the mobilestation performs channel estimation across a greater number of physicalresource blocks for a particular precoder. In an advantageous embodimentof the present disclosure, a bundle size from one (1) to three (3) PRBsprovides the necessary tradeoff between precoding flexibility andchannel estimation.

In an advantageous embodiment of the present disclosure, the bundlingsize is determined by, or is a function of, a downlink system bandwidthconfiguration. As the system bandwidth increases, the bundling size alsoincreases. In a preferred embodiment, the bundling size is alsodetermined by the resource block group (RBG) size (i.e., the size ofvirtual resource blocks). FIGS. 8A, 8B and 8B illustrate TABLES 1-3,respectively, which provide examples of bundling sizes determined bydownlink system bandwidth configuration and RBG size. In TABLE 1, asystem bandwidth that is below a first threshold equal to eleven (11)physical resource blocks (PRBs) uses a bundling size of M=1 PRB. Asystem bandwidth that is greater than or equal to the first threshold,but less than a second threshold (i.e., from 11 to 63 PRBs) uses abundling size of M=2 PRBs. A system bandwidth that is greater than thethird threshold (i.e., from 64 to 110 or more) of physical resourceblocks uses a bundling size of M=3 PRBs.

In an alternate embodiment shown in TABLE 2, a system bandwidth lessthan the first threshold (i.e., 10 or less PRBs) uses a bundling size ofM=1 PRB, whereas a system bandwidth greater than the first threshold(i.e., 11 or more) uses a bundling size of M=2 PRBs.

In another embodiment shown in TABLE 3, the bundling size is determinedas a function of downlink system bandwidth configuration, includingresource block group (RBG) size=P). A system bandwidth below a firstthreshold (10 or less PRBs) and RBG size, P=1, uses a bundling size ofM=1 PRB. A system bandwidth greater than or equal to the firstthreshold, but less than a second threshold (i.e., 11 to 26 PRBs) andRBG size, P=2, uses a bundling size of M=2 PRBs. A system bandwidthgreater than or equal to the first threshold, but less than a secondthreshold (i.e., 27 to 63 PRBs) and RBG size, P=3, uses a bundling sizeof M=3 PRBs.

Finally, a system bandwidth greater than the fourth threshold (i.e., 64or more PRBs) and RBG size, P=4, uses a bundling size of M=2 PRBs. Inthis last example, even though the system bandwidth and RBG size areincreased, the bundling size is reduced to 2. This is to ensure that thebundling size (2) is evenly divisible into the RBG size (4). If abundling size of 4 PRBs had been used, too much precoder flexibilitywould be lost, since the same precoder would have to be used in all 4PRBs. However, an RGB size of 4 PRBs would not be evenly divided by abundling size of 3 PRBs. As a result, one bundle of 3 PRBs would use oneprecoder and another bundle of only 1 PRB would use another precoder,which would cause channel estimation to suffer.

A bundling size of M=2 means that every pair of physical resource blocksis bundled, irrespective of the total system bandwidth. FIG. 5illustrates a bundling size of M=2. In FIG. 5, different pairs ofphysical resource blocks are bundled together in bundle B1, bundle B2,bundle B3, etc. For example, physical resource blocks PRBO and PRB1 arein bundle B1, physical resource blocks PRB2 and PRB3 are in bundle B2,and so forth. The mobile station may assume, by default setting, thatthe PRBs in the same bundle use the same precoders. By way of example,the mobile station assumes that PRBO and PRB1 use the same precoders(i.e., same precoding subset), since PRBO and PRB1 are in the samebundle. The PRBs in different bundles may use different precoders.

Let M be the fixed bundling size of the PRB bundling. Then the totalnumber of precoding subsets in the downlink (N_(PB) ^(DL)) is:

${N_{PB}^{DL} = \left\lceil \frac{N_{RB}^{DL}}{M} \right\rceil},$

where N_(RB) ^(DL) is the downlink bandwidth configuration.

Accordingly, the precoding subset of i, where

${i = 0},\ldots \mspace{14mu},\left\lfloor \frac{N_{RB}^{DL}}{M} \right\rfloor,$

consists of PRBs where the PRB number (n_(PRB)) in the frequency domainis:

M×i, . . . ,M×(i+1)−1.

Accordingly, upon reception of the downlink resource allocation, amobile station performs channel estimation and demodulation based on thevalue n_(PRB), the value M, the resource allocation type, and thevirtual resource block type.

For example, for resource allocation type 0 and 2 under localizedvirtual resource blocks, the mobile station may assume the same precoderfor the downlink assigned PRBs which fall into the same precodingsubset, as described for FIG. 5.

FIG. 6 illustrates bundling of physical resource blocks for a particularresource allocation and virtual resource blocks of localized typeaccording to an embodiment of the disclosure. In FIG. 6, the mobilestation is configured to receive Type 0 resource allocation underlocalized virtual resource allocation type. More specifically, themobile station receives resource allocation of resource block groupsRBG1 and RBG2, which consist of physical resource blocks PRBO, PRB1,PRB2, PRB3, PRB4 and PRB5. For the case where M=2, the mobile stationmay assume that PRBO and PRB1 have the same precoder because RPBO andPRB1 are both in bundle B1. The mobile station may also assume that PRB2and PRB3 have the same precoder because RPB2 and PRB2 are both in bundleB2. Finally, the mobile station may assume that PRB4 and PRB5 have thesame precoder because RPB4 and PRB5 are both in bundle B3.

FIG. 7 illustrates bundling of physical resource blocks for a particularresource allocation and virtual resource blocks of localized typeaccording to another embodiment of the disclosure. In FIG. 7, the mobilestation is configured to receive Type 2 compact resource allocationunder localized virtual resource type. More specifically, the mobilestation is configured to receive physical resource blocks PRB1, PRB2 andPRB3 for the physical downlink shared channel (PDSCH). For the casewhere M=2, as shown in FIG. 7, the mobile station may assume that PRB2and PRB3 have the same precoder since PRB1 and PRB2 are in the sameprecoding subset (i.e., same bundle B2). However, for PRB1, the mobilestation may assume PRB1 uses a different precoder for channel estimationpurposes, since PRB1 is in bundle B1.

For the case of virtual resource blocks of distributed type, the mobilestation may assume that PRB bundling is off and would assume that eachPRB will have a different precoder.

For the case of Type 1 resource allocation, the same approach shown inthe previous examples may apply, so that the mobile station may assumethe same precoder for the PRBs that fall in the same precoding subset.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

1.-21. (canceled)
 22. A method for communication, the method comprising:allocating a resource based on a resource block group for resourceallocation; and applying a same precoder to all physical resource blockswithin a resource block group for resource block bundling, wherein anumber of resource block within the resource block group for resourceblock bundling and a number of resource block within a resource blockgroup for resource allocation is 1 if a system bandwidth is less than orequal to 10 resource blocks, wherein the number of resource blockswithin the resource block group for resource block bundling and thenumber of resource blocks within the resource block group for resourceallocation is 2 if the system bandwidth is between 11 and 26, whereinthe number of resource blocks within the resource block group forresource block bundling and the number of resource blocks within theresource block group for resource allocation is 3 if the systembandwidth is between 27 and 63, and wherein the number of resourceblocks within the resource block group for resource block bundling is 2and the number of resource blocks within the resource block group forresource allocation is 4 if the system bandwidth is between 64 and 110.23. The method of claim 22, wherein if the number of resource blockswithin the resource block group for resource block bundling is M, atotal number of resource block groups for resource block bundling(N_(PB) ^(DL)) is defined based on${N_{PB}^{DL} = \left\lceil \frac{N_{RB}^{DL}}{M} \right\rceil},$ whereN_(RB) ^(DL) is the system bandwidth.
 24. The method of claim 22,wherein a last resource block within a last resource block group forresource block bundling is determined based on N_(RB) ^(DL), whereN_(RB) ^(DL) is the system bandwidth.
 25. The method of claim 22,wherein resource block bundling is available if a transmission modesupporting up to 8 antenna ports is configured.
 26. The method of claim22, wherein resource allocation is based on virtual resource blocks of adistributed type or virtual resource blocks of a localized type.
 27. Abase station, comprising: a transmit path circuitry configured to:allocate resources based on a resource block group for resourceallocation; and apply a same precoder to all resource blocks within aresource block group for resource block bundling, wherein a number ofresource blocks within the resource block group for resource blockbundling and a number of resource blocks within a resource block groupfor resource allocation is 1 if a system bandwidth is less than or equalto 10 resource blocks, wherein the number of resource blocks within theresource block group for resource block bundling and the number ofresource blocks within the resource block group for resource allocationis 2 if the system bandwidth is between 11 and 26, wherein the number ofresource blocks within the resource block group for resource blockbundling and the number of resource blocks within the resource blockgroup for resource allocation is 3 if the system bandwidth is between 27and 63, and wherein the number of resource blocks within the resourceblock group is 2 and the number of resource blocks within the resourceblock group for resource allocation is 4 if the system bandwidth isbetween 64 and
 110. 28. The base station of claim 27, wherein if thenumber of resource blocks within the resource block group for resourceblock bundling is M, a total number of resource block groups forresource block bundling (N_(PB) ^(DL)) is defined based on${N_{PB}^{DL} = \left\lceil \frac{N_{RB}^{DL}}{M} \right\rceil},$ whereN_(RB) ^(DL) is the system bandwidth.
 29. The base station of claim 27,wherein a last resource block within a last resource block group forresource block bundling is determined based on N_(RB) ^(DL), whereN_(RB) ^(DL) is the system bandwidth.
 30. The base station of claim 27,wherein application of the same precoder by the transmit path circuitryto all resource blocks within the resource block group for resourceblock bundling is available if a transmission mode supporting up to 8antenna ports is configured.
 31. The base station of claim 27, whereinthe transmit path circuitry allocates resources based on virtualresource blocks of a distributed type or virtual resource blocks of alocalized type.
 32. A method for communication, the method comprising:receiving resource allocation based on a resource block group forresource allocation; and assuming a same precoder is applied to allresource blocks within a resource block group for resource blockbundling, wherein a number of resource blocks within the resource blockgroup for resource block bundling and a number of resource blocks withina resource block group for resource allocation is 1 if a systembandwidth is less than or equal to 10 resource blocks, wherein thenumber of resource blocks within the resource block group for resourceblock bundling and the number of resource blocks within the resourceblock group for resource allocation is 2 if the system bandwidth isbetween 11 and 26, wherein the number of resource blocks within theresource block group for resource block bundling and the number ofresource blocks within the resource block group for resource allocationis 3 if the system bandwidth is between 27 and 63, and wherein thenumber of resource blocks within the resource block group is 2 and thenumber of resource blocks within the resource block group for resourceallocation is 4 if the system bandwidth is between 64 and
 110. 33. Themethod of claim 32, wherein if the number of resource blocks within theresource block group for resource block bundling is M, a total number ofresource block groups for resource block bundling (N_(RB) ^(DL)) isdefined based on${N_{PB}^{DL} = \left\lceil \frac{N_{RB}^{DL}}{M} \right\rceil},$ whereN_(RB) ^(DL) is the system bandwidth.
 34. The method of claim 32,wherein a last resource block within a last resource block group forresource block bundling is determined based on N_(RB) ^(DL), whereN_(RB) ^(DL) is the system bandwidth.
 35. The method of claim 32,wherein the same precoder is assumed to be applied to all resourceblocks within a resource block group for resource block bundling if atransmission mode supporting up to 8 antenna ports is configured. 36.The method of claim 32, wherein the received resource allocation basedon the resource block group for resource allocation is based on virtualresource blocks of a distributed type or virtual resource blocks of alocalized type.
 37. A mobile station, comprising: a receive pathcircuitry configured to: receive resource allocation based on a resourceblock group for resource allocation; and assume a same precoder isapplied to all resource block within a resource block group for resourceblock bundling, wherein a number of resource blocks within the resourceblock group for resource block bundling and a number of resource blockswithin a resource block group for resource allocation is 1 if a systembandwidth is less than or equal to 10 resource blocks, wherein thenumber of resource blocks within the resource block group for resourceblock bundling and the number of resource blocks within the resourceblock group for resource allocation is 2 if the system bandwidth isbetween 11 and 26, wherein the number of resource blocks within theresource block group for resource block bundling and the number ofresource blocks within the resource block group for resource allocationis 3 if the system bandwidth is between 27 and 63, and wherein thenumber of resource blocks within the resource block group is 2 and thenumber of resource blocks within the resource block group for resourceallocation is 4 if the system bandwidth is between 64 and
 110. 38. Themobile station of claim 37, wherein if the number of resource blockswithin the resource block group for resource block bundling is M, atotal number of resource block groups for resource block bundling(N_(PB) ^(DL)) is defined based on${N_{PB}^{DL} = \left\lceil \frac{N_{RB}^{DL}}{M} \right\rceil},$ whereN_(RB) ^(DL) is the system bandwidth.
 39. The mobile station of claim37, wherein a last resource block within a last resource block group forresource block bundling is determined based on N_(RB) ^(DL), whereN_(RB) ^(DL) is the system bandwidth.
 40. The mobile station of claim37, wherein the receive path circuitry assumes a same precoder isapplied to all resource blocks within a resource block group forresource block bundling if a transmission mode supporting up to 8antenna ports is configured.
 41. The mobile station of claim 37, whereinthe receive path circuitry is configured to receive resource allocationbased on virtual resource blocks of a distributed type or virtualresource blocks of a localized type.